Many exercising devices are known which utilize compression resistance to afford physical exercise for the hands and/or feet of persons utilizing the same. Some of these devices are shown in U.S. Pat. Nos. 1,549,710; 2,944,530; 3,265,389; 3,413,243; 3,658,326; 3,910,572 and 4,040,619.
G. Campbell shows in U.S. Pat. No. 1,549,710 a physical apparatus for developing the muscles and tendons of the fingers, hands, wrists and forearms. This apparatus includes a solid hand grip of a length commensurate with the width of the hand and of elongated form and transverse dimensions appropriate to the application. The grip is constructed of resilient sponge rubber to resist the closing pressure of the fingers to promote muscular strain for the development of muscles.
M. Cohan in U.S. Pat. No. 2,944,530 discloses a device for developing a bowler's grip. The developer disclosed comprises opposed thumb and finger grip members and a compressible resilient pad interposed between and connected to the opposed inner ends of the grip member. There are provided various grooves in different positions and of different designs to accommodate the different fingers of the user.
In U.S. Pat. No. 3,265,389, E. Carlson reveals a hand exerciser, the purpose of which is to incorporate a novel shape and characteristics which enable it to be manipulatively held in various positions for exercising different parts of the hand. The exerciser moreover has different portion of unlike compressibility thereby causing a somewhat sequential compressive action of the device as it is squeezed.
D. Griffin shows an orthopedic exercising device in U.S. Pat. No. 3,413,243. The device is in the form of a ball formed of interconnected air cells defined by resilient wall membranes. The cells at the periphery of the ball are maintained normally closed to preclude passage of air from within the mass constituting the ball and are opened for expelling and absorbing air on compression of, and relaxation of pressure on the mass.
In U.S. Pat. No. 3,658,326, T. Fawick discloses a hand exercising device constructed of a pair of air-filled rubber bulbs for respective hands. A small passageway connects the bulbs and is longitudinally stretchable. One of the bulbs includes a check valve which opens if the air pressure in the device drops below atmospheric pressure.
In U.S. Pat. No. 3,910,572 is furthermore disclosed by H. Denier a flexible, compressible, hollow bulb of rubber which can be held in the hand and squeezed from a normally expanded to a collapsed condition. A bleed valve is provided in the bulb to provide a restricted air duct through which air may be expelled from the bulb when the bulb is squeezed.
J. Landi discloses in U.S. Pat. No. 4,040,619 a flexible and resilient manually collapsible transparent hour-glass shaped housing containing a loosely held liquid-saturated sponge in each of two chambers of the housing. One chamber is squeezed to drive liquid from one chamber to the other and then the device can be inverted to repeat the exercise.
None of the above devices are particularly suitable for physical therapy selectively with the hands or feet or other such extremities of the operator of the same and none of the aforegoing devices are particularly suitable for adjustment both with respect to compressibility and with respect to angular disposition of the forces of compression relative to the operating extremity.